Best screws to tighten up a 3/4" subfloor

I am about to put in a wood floor in a second floor room. I want to screw down the existing 3/4" subfloor to the joists. The floors squeak badly from poor workmanship. What are the best screws to use for this.

Best screws to tighten up a 3/4" subfloor

If possible you should glue the subfloor to the joist to eliminate squeak. Screws are not enough to fix it permanently.

Usually it is not possible to pull up a subfloor to do it properly so adding more screws will help lessen the squeaks now that the wood has all dried and settled. There are application specific flooring screws that have two tracks of teeth at different depths available. They are not much better than standard wood construction or deck screws for this, they supposedly speed up installation time as they are self drilling but hold no better or worse than a standard deck screw.

I had access to one section of squeaky subfloor in my home where we could access it from unfinished basement below. I removed all the existing fasteners and was able to get a bead of glue in from below before going back to refasten. The bedrooms had no such access so we only added screws from the top while doing a carpet replacement and after about 6 years they are squeaking just as much as before. Humidity changes and temperature swings seems to be the long term problem. Mechanical fasteners just are not enough to combat this seasonal movement and eventually the squeaks return.

If you read the installation instructions for an engineered joist system (we have the so called silent floor I-beam style joists) it requires glue. So the builder of our house clearly skipped that step. I think these systems were still relatively new when our house was built in the early 90's and the builders probably thought they were some kind of magic that meant they just had to screw down the subfloor and it would work.

Subfloor on properly sized and structured joists that is glued with a good poly based adhesive will almost never squeak.